Quetta/Islamabad, Aug. 9 (Reuters): Pakistan today began burying 74 people, most of them lawyers, killed in an attack on a hospital in the southwestern city of Quetta, as lawyers staged a nationwide strike and heaped pressure on the government to do more against militants.

Medical staff said up to 60 of those killed in yesterday's bombing at a government hospital were lawyers who had gathered to mourn the assassination earlier that day of the president of the Baluchistan Bar Association, Bilal Anwar Kasi.

This morning, four of over one hundred people wounded, including two more lawyers, died in hospital, taking the toll to 74, said Abdul Rehman, the medical superintendent at the Civil Hospital, Quetta.

Shops, businesses, schools and universities in the city and beyond remained closed as the government announced three days of mourning.

The Islamic State was one of two militant groups to claim responsibility for the atrocity, although officials and analysts said they doubted whether the West Asia-based movement was behind the blast.

It was the deadliest militant attack in Pakistan this year and the latest in a string of strikes on lawyers, seen by some militants as an extension of the state and so legitimate targets.

At the Civil Hospital in Quetta, windows were shattered and blood still stained the walls and floor a day after the attack. Shreds of ripped black cloth from slain lawyers' suits littered the ground.

Rehman said that last year the hospital had requested paramilitary soldiers be stationed there for security.

"We briefed ... security officials," the medic said. "They said, 'We'll see what's possible.'"

At one lawyer's funeral on the outskirts of Quetta, the cleric leading prayers chanted: "May all the terrorists who carried out this heinous attack meet true justice."

Ghulam Ghaus Qadri, who came to say his final goodbyes to his friend Rashid Khokher, a lawyer who died in the blast, added: "For how long will we carry these bodies? I'd like to ask the government, for God's sake, these attacks must not happen." At a protest outside the Supreme Court in the capital Islamabad, Ashtar Ausaf Ali, Pakistan's attorney general, called the attackers "weak and pathetic".

"They should know that the nation and the legal community are united against them," he said. Supreme Court Bar president Ali Zafar called for the government to do more to protect lawyers.